I didn't get any further than that with these answers because it turns out, perhaps not surprisingly, that with 15 letters to work with, you can create some pretty amazing anagrams. I opted to makes these fairly straightforward, prioritizing ease of solving over misdirection.
The two 15-letter clues I wound up with are:
Irresolute aunts playing dangerous game of chance (7, 8)
That greenish art arrangement? Revolutionary! (15)
And of course if you don't know how to solve cryptics yet, try my tutorial! It's free and straight-forward. For lessons from a true master, order a copy of David Astle's book "Puzzled".